如何在golang中正确使用os.Args？

Question

I need to use config in my go code and I want to load config path from command-line. I try:

if len(os.Args) > 1 { 
        configpath := os.Args[1]
        fmt.Println("1") // For debug
    } else {
        configpath := "/etc/buildozer/config"
        fmt.Println("2")
    }

Then I use config:

configuration := config.ConfigParser(configpath)

When I launch my go file with parameter (or without) I receive similar error

# command-line-arguments
src/2rl/buildozer/buildozer.go:21: undefined: configpath

How should I correctly use os.Args?

Answer 1

Define configPath outside the scope of your if.

configPath := ""

if len(os.Args) > 1 { 
  configpath = os.Args[1] 
  fmt.Println("1") // For debug 
} else { 
  configpath = "/etc/buildozer/config"
  fmt.Println("2") 
}

Note the 'configPath =' (instead of :=) inside the if.

That way configPath is defined before and is still visible after the if.

See more at "Declarations and scope" / "Variable declarations".